CN114735811A

CN114735811A - Culture method of short-cut nitrification activated sludge with high accumulation rate

Info

Publication number: CN114735811A
Application number: CN202210297622.XA
Authority: CN
Inventors: 杨宏; 王泊含
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2022-03-23
Filing date: 2022-03-23
Publication date: 2022-07-12
Anticipated expiration: 2042-03-23
Also published as: CN114735811B

Abstract

A culture method of short-cut nitrification activated sludge with high accumulation rate belongs to the field of water treatment. The method is characterized in that activated sludge of a sewage treatment plant is used as a seed source, the structural characteristics of the original shortcut nitrification (AOB) flora are kept, an FA inhibition starting method which is kept standing for 24 hours is adopted to help the AOB flora to establish an advantage status, the growth of Nitrite Oxidizing Bacteria (NOB) is inhibited by using high FNA under the operation condition of high Dissolved Oxygen (DO), the high accumulation rate is maintained, sludge is discharged through regulation, and then the NOB is eliminated through regular sludge discharge on the premise of keeping the high ammonia oxidation rate of the system, so that the AOB is enriched rapidly, and the culture of the shortcut nitrification activated sludge with the high accumulation rate is realized.

Description

Culture method of short-cut nitrification activated sludge with high accumulation rate

Technical Field

The invention belongs to the field of water treatment, and particularly relates to a method for culturing high-accumulation-rate short-cut nitrifying activated sludge.

Background

With the continuous improvement of the industrialization level in China, the efficient and stable removal of ammonia nitrogen pollutants in industrial sewage becomes a focus of attention in the field of water treatment. In sewage treatment, the nitrogen in water can be removed only by complete nitrification and denitrification in the traditional denitrification process, namely, ammonia nitrogen in the water body is oxidized into nitrite, the nitrite is oxidized into nitrate, and finally the nitrate is reduced into nitrogen under the action of denitrifying bacteria. However, with the progress of biological research, a plurality of novel denitrification processes based on short-cut nitrification appear. The short-cut nitrification is that after ammonia nitrogen is oxidized into nitrite under the action of Ammonia Oxidizing Bacteria (AOB), subsequent nitrification is not carried out, and NO 2-is used as an electron acceptor in the subsequent denitrification process. Compared with the traditional biological nitrification, the short-cut nitrification can achieve the purposes of saving energy and reducing aeration quantity and carbon source consumption, and greatly improves the treatment level of ammonia nitrogen sewage, and the realization of the process depends on Ammonia Oxidizing Bacteria (AOB). In the existing short-range nitrification research, a high-efficiency AOB single bacterium is mostly taken as a core, and a system experiment is carried out by a technical route of screening, culturing, enriching and adding. This technical route presents certain problems: the single strain has poor adaptability to the environment, namely the single strain AOB is difficult to maintain the long-acting advantage of the strain in a treatment system with complex sewage components and a large amount of mixed bacteria.

At present, the traditional AOB acclimatization culture and rapid enrichment mode is small-scale culture, nitrite nitrogen (FNA) is controlled to be maintained at a high expression level, Dissolved Oxygen (DO) is maintained at a low oxygen level, and by utilizing the principle that the competitive power of AOB to DO under the condition of low dissolved oxygen (less than 0.5mg/L) supply is higher than that of NOB, nitrite is stably and highly accumulated, and the aim of high nitrite nitrogen accumulation rate is fulfilled. However, such culture methods have a long period of time, the rate of ammonia oxidation in the system is inhibited by low dissolved oxygen, the reaction efficiency is low, and the bacterial yield is small, which is not ideal for practical large-scale production.

Disclosure of Invention

The invention aims to develop a technical method for culturing short-range nitrified activated sludge with high accumulation rate, which adopts an industrial-grade reactor, inhibits the growth of NOB at the initial culture stage by a starting method of FA inhibition after standing for 24 hours, and lays a foundation for establishing flora advantages for AOB; the high DO provides for the achievement of large consumption of heterotrophic bacteria and the maintenance of high ammonia oxidation rates; the NOB increment is controlled by controlling nitrite nitrogen (FNA) periodically, and the flora advantage of AOB is maintained; NOB in the system is effectively eliminated through a regular sludge discharge mode. The method can realize the culture of the short-range nitrified activated sludge with high accumulation rate in a short time.

The invention adopts activated sludge as a seed source to keep the structural characteristics of the original AOB flora, adopts a high DO method to keep higher ammoxidation efficiency, inhibits the growth of NOB by utilizing high FNA under the condition of high DO, and realizes the elimination of NOB by regularly discharging sludge under the condition of keeping the system activity at a high rate.

The culture method of the short-cut nitrification activated sludge with high accumulation rate comprises the following steps:

(1) the returned sludge of the sewage plant is used as a strain source, and is cultured by using an industrial reactor for 24 hours to inhibit FA (microbial enzyme) so that the growth of NOB (NodeB) is inhibited and even dies, thereby helping AOB to establish the dominant position of a flora; the effectiveness of the starting method is detected according to the concentration change ratio of nitrite nitrogen and nitrate nitrogen in the effluent clarified liquid of the sampling port, namely the nitrite nitrogen accumulation rate; in the process, the NOB activity in the sludge is higher before starting, a period of time is needed for activity recovery after inhibition, the uninhibited AOB is rapidly proliferated along with the operation of the reactor, and nitrite nitrogen rapidly grows in the initial culture stage; when the NOB activity is recovered, the nitrite nitrogen accumulation rate measured by the effluent supernatant tends to be stable and is maintained at 89%, and the process reflects that the AOB is established at a dominant position quickly;

(2) performing inorganic culture of AOB on the sludge in the step (1), wherein the feed water comprises a basic solution and a trace element culture solution, wherein the basic solution comprises NH4Cl serving as a nitrogen source and KH2PO4 serving as a phosphorus source, the dosage of the basic solution depends on the change of the ammonia nitrogen concentration in a shortcut nitrification sludge culture system, and the basic solution is 50 mg.L^-1The unit concentration is as follows: NH (NH)₄Cl 156.5mg·L^-1、KH₂PO₄ 31.30mg·L^-1、CaCl₂ 10mg·L^-1、MgSO₄·7H₂O 10mg·L^-1(ii) a Adding 1.0mL of trace element culture solution into each liter of shortcut nitrification sludge culture system, wherein the culture solution comprises the following components: ZnSO₄·7H₂O 0.12mg·L^-1、Na₂MoO₄·2H₂O 0.12mg·L^-1、CoCl₂·6H₂O 0.15mg·L^-1、FeCl₃·6H₂O 1.50mg·L^-1、CuSO₄·5H₂O 0.03mg·L^-1、NiCl₂·6H₂O 0.12mg·L^-1、Mn₂SO₄·H₂O 0.12mg·L^-1；

By adopting a high dissolved oxygen operation mode, the concentration of substrate ammonia nitrogen is controlled to be 30 +/-5.0 mg/L by controlling the pH value in the reactor to be 8.00 +/-0.10, the temperature to be 25 ℃ and the DO to be 1.5 +/-0.10 mg/L and continuously adjusting the concentration of inlet water, thereby providing an optimal condition for the growth of AOB; in the initial stage of culture, the concentration of the short-cut nitrified sludge is low, FNA inhibition cannot be formed, the short-cut nitrified sludge can only enter a logarithmic growth period in a short time, the advantages of the flora are enlarged, the sludge concentration acceleration rate is increased from 5% to 10%, the nitrite nitrogen accumulation rate is increased to about 91%, and the short-cut nitrified sludge enters an enrichment stage.

(3) And (3) on the basis of the step (2), other conditions are controlled to be unchanged, the NOB is only inhibited by the FNA value in the sludge washing control reactor at regular intervals, the flora advantage of the AOB is stabilized and expanded, and sludge is discharged at regular intervals and ceaselessly during the period, so that the short-cut nitrified sludge amount in the system is continuously increased. Along with the continuous improvement of the ammonia oxidation capacity of the system, the specific ammonia oxidation rate of the system reaches 20.00 mg.g^-1·h^-1And even above, and the nitrite nitrogen accumulation rate was maintained at 95%. The sludge discharge times are increased continuously, so that NOB is gradually elutriated from the system, and the culture of the short-cut nitrified sludge with high accumulation rate is realized.

The invention has the advantages of

(1) When the culture is started, standing for 24h for FA inhibition to inhibit the growth of NOB and even kill the NOB, thereby helping the AOB to establish the dominant position of flora;

(2) in the initial stage of culture, controlling DO at a higher level, keeping proper pH, temperature and substrate concentration, and rapidly enriching AOB so as to realize high accumulation rate of the shortcut nitrification activated sludge;

(3) after a certain amount of nitrite is accumulated, the growth of NOB is controlled by using FNA through pH and the nitrite nitrogen content of the system. At this time, the setting of high DO continuously increases the ammoxidation rate of AOB, so that the nitrite accumulation rate of the short-cut nitrification activated sludge can be stably, efficiently and persistently expressed.

(4) The NOB is elutriated out of the system in a regular sludge discharge mode to obtain relatively pure AOB, and the corresponding stability can be maintained in any system;

(5) taking nitrified activated sludge of a sewage treatment plant as a seed source, and screening and enriching to obtain short-range nitrified sludge keeping the original AOB flora composition characteristics;

(6) because the shortcut nitrification sludge has higher ecological stability to the high ammonia nitrogen wastewater, compared with the traditional whole-course nitrification process, the shortcut nitrification sludge omits the subsequent nitrification, directly carries out denitrification, has a relatively stable high accumulation rate system and a high ammonia oxidation rate, and can greatly simplify the treatment process and the operation cost.

Drawings

FIG. 1 is a diagram of a high accumulation rate short-cut nitrification activated sludge culture apparatus;

1 a screw pump; 2, a gas storage tank; 3, a stirring motor; 4, a reactor; 5, an aeration ring; 6 dissolved oxygen probe; 7pH probe; 8, a temperature probe; 9PCL self-control cabinet; 10DO transmitter; 11 a pH transmitter; 12 a temperature transmitter; 13 adding an alkali metering pump; 14, an alkali box; 15 dosing a metering pump; 16 medicine boxes; 17 air inlet pipes; 18 an alkali feeding pipe; 19 a medicine inlet pipe; 20 an alkali inlet pipe; 21 an inlet and outlet port; 22 a sludge discharge port.

Detailed Description

The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1

The experiment shows that the device is shown in figure 1, the effect is obvious, and the specific operation is as follows:

(1) performing FA inhibition for 24h by using industrial-grade reactor, wherein the nitrite nitrogen accumulation rate of sludge is increased from 82% to 91%, the sludge concentration (MLSS) is increased from 1205mg/L to 2457mg/L, and the specific ammonia oxidation rate is increased from 5.30mg g^-1·h^-1Increased to 7.5mg g^-1·h^-1The apparent conditions indicated that the growth of NOB was inhibited and the flora of AOB was predominantly established.

(2) On the basis of the step (1), a high dissolved oxygen operation mode is adopted, the pH value in the reactor is controlled to be 8.00 +/-0.10, the temperature is 25 ℃,DO is 1.5 +/-0.10 mg/L, the concentration of inlet water is continuously adjusted, the concentration of substrate ammonia nitrogen is controlled to be 30 +/-5.0 mg/L, and the optimal condition is provided for the growth of AOB. The ammoxidation rate of the reactor was from 20.25 mg.L^-1·h^-1Logarithmically increasing to 140.13 mg.L^-1·h^-1The sludge concentration is increased from 2457mg/L to 7000mg/L, the nitrite nitrogen accumulation rate is kept around 91%, and the rapid enrichment stage of the short-cut nitrification sludge is shown.

The feed water component comprises NH₄Cl is used as nitrogen source and KH₂PO₄The basic solution is a phosphorus source and a trace element culture solution, the dosage of the basic solution depends on the change of ammonia nitrogen concentration in a short-cut nitrification sludge culture system, and the basic solution is 50 mg.L^-1The mass concentration of the components is as follows: NH (NH)₄Cl 156.5mg·L^-1、KH₂PO₄ 31.30mg·L^-1、CaCl₂ 10mg·L^-1、MgSO₄·7H₂O 10mg·L^-1. 1.0mL of trace element culture solution is added into each liter of short-range nitrification sludge culture system, and the culture system comprises the following components: ZnSO₄·7H₂O 0.12mg·L^-1、Na₂MoO₄·2H₂O 0.12mg·L^-1、CoCl₂·6H₂O 0.15mg·L^-1、FeCl₃·6H₂O 1.50mg·L^-1、CuSO₄·5H₂O 0.03mg·L^-1、NiCl₂·6H₂O 0.12mg·L^-1、Mn₂SO₄·H₂O 0.12mg·L^-1。

(3) On the basis of the step (2), other conditions are controlled to be unchanged, and the FNA in the reactor is kept at 0.1 mg.L by periodically washing mud^-1To 1.0 mg. L^-1Meanwhile, NOB is kept inhibited, AOB is prevented from being inhibited, and sludge is discharged continuously at regular intervals, so that the quantity of short-cut nitrified sludge in the system is continuously increased. At the moment, the nitrite accumulation rate is improved to 94 percent and maintained for a long time, and the specific ammonia oxidation rate is improved to 20.30mg g^-1·h^-1It shows that the activity of AOB in the sludge is continuously enhanced and the proportion of AOB in the sludge is continuously increased.

Claims

1. A method for culturing short-cut nitrification activated sludge with high accumulation rate is characterized by comprising the following steps:

(1) the returned sludge of the sewage plant is used as a strain source, and is cultured by an industrial-grade reactor for 24 hours to inhibit FA (microbial enzyme) so that the growth of NOB is inhibited and even dies, thereby helping AOB to establish the dominant position of a flora; the effectiveness of the starting method is detected according to the concentration change ratio of nitrite nitrogen and nitrate nitrogen in the effluent clarified liquid of the sampling port, namely the nitrite nitrogen accumulation rate; in the process, the NOB activity in the sludge is higher before starting, a period of time is needed for activity recovery after inhibition, the uninhibited AOB is rapidly proliferated along with the operation of the reactor, and nitrite nitrogen rapidly grows in the initial culture stage; when the NOB activity is recovered, the nitrite nitrogen accumulation rate measured by the effluent supernatant tends to be stable and is maintained at 89%, and the process reflects that the AOB has quickly established an advantage position;

(2) performing inorganic culture of AOB on the sludge in the step (1), wherein the feed water comprises a basic solution and a trace element culture solution, wherein the basic solution comprises NH4Cl serving as a nitrogen source and KH2PO4 serving as a phosphorus source, the dosage of the basic solution depends on the change of the ammonia nitrogen concentration in a shortcut nitrification sludge culture system, and the basic solution is 50 mg.L^-1The unit concentration is as follows: NH₄Cl 156.5mg·L^-1、KH₂PO₄31.30mg·L^-1、CaCl₂ 10mg·L^-1、MgSO₄·7H₂O 10mg·L^-1(ii) a Adding 1.0mL of trace element culture solution into each liter of shortcut nitrification sludge culture system, wherein the culture solution comprises the following components: ZnSO₄·7H₂O 0.12mg·L^-1、Na₂MoO₄·2H₂O 0.12mg·L^-1、CoCl₂·6H₂O 0.15mg·L^-1、FeCl₃·6H₂O 1.50mg·L^-1、CuSO₄·5H₂O 0.03mg·L^-1、NiCl₂·6H₂O 0.12mg·L^-1、Mn₂SO₄·H₂O 0.12mg·L^-1；

By adopting a high dissolved oxygen operation mode, the concentration of ammonia nitrogen in a substrate is controlled to be 30 +/-5.0 mg/L by controlling the pH value in the reactor to be 8.00 +/-0.10, the temperature to be 25 ℃ and the DO to be 1.5 +/-0.10 mg/L and continuously adjusting the concentration of inlet water, thereby providing an optimal condition for the growth of AOB; in the initial stage of culture, the concentration of the short-cut nitrified sludge is low, FNA inhibition cannot be formed, the short-cut nitrified sludge can only enter a logarithmic growth period in a short time, the advantage of the flora is enlarged, the sludge concentration acceleration rate is increased from 5% to 10%, the nitrite nitrogen accumulation rate is increased to 91%, and the short-cut nitrified sludge enters an enrichment stage;

(3) on the basis of the step (2), other conditions are controlled to be unchanged, the NOB is only inhibited by controlling the FNA value in the reactor through regular sludge washing, the flora advantage of the AOB is stabilized and expanded, and sludge is discharged regularly and uninterruptedly in the period, so that the short-cut nitrified sludge amount in the system is still increased continuously; along with the continuous improvement of the ammonia oxidation capacity of the system, the specific ammonia oxidation rate of the system reaches 20.00 mg.g^-1·h^-1And even above, and the nitrite nitrogen accumulation rate was maintained at 95%. The sludge discharge times are increased continuously, so that NOB is gradually elutriated from the system, and the culture of the short-cut nitrified sludge with high accumulation rate is realized.